A two-step self consistent algorithm for extracting magnetic anisotropy constants from angle-dependent ferromagnetic resonance measurements

To infer anisotropy parameters of magnetic materials from experimental measurements of ferromagnetic resonance (FMR) (with data comprising resonant frequencies and corresponding resonant magnetic fields), a fitting procedure to the theoretical model is essential. The governing equation for this fitting process is the Smit–Beljers equation (SB equation), which links FMR frequencies to resonant magnetic field values and anisotropy parameters nonlinearly, and through the equilibrium magnetization angle values, which also depend on the same anisotropy parameters and magnetic field values. Obtaining an analytical expression for this equation is rarely possible. In this paper, we address the challenges posed by the Smit–Beljers equation and propose a two-step self-consistent algorithm to extract the relevant parameters efficiently.